The purpose of a bleed resistor is to .. well, errrr, "bleed" of any
residual charge from a capacitor bank thus eliminating possible shock hazard
to the operator. Sufficient protection would be afforded if the charge
could be bled off in, say 30 seconds. The universal time constant is given
as: T = RxC; transposing gives R = T/C. A cap is said to be fully charged
or discharged after 5 time constants. Therefore the desired RC time constant
of each cap and a bleeder resistor is 6 seconds. Assuming the value of each
of the 7 caps is 120 microfarad, the resistor value is figured as R = T/C,
or R = (6 / 0.000120) = 50000 ohms. The nearest size standard value is 56
K. Figure the power dissipated by each resistor as (E squared) / R; or P =
(240 squared) / 56K = aprox. 1 watt. You would need a 56K, 2 Watt bleeder
resistor across each of the 7 caps. Another way to do it would be place a
single 56K, 10 Watt resistor across the cap bank. All this represents a
power loss of around 7 watts if the bleeder resistor(s) is in circuit
constantly. The bleeder could be applied via a N.C. set of relay contacts
only after shut down, if desired, rather than leaving it in circuit
constantly.

Bob Swinney